While in Colditz, Élie had written to his childhood sweetheart Baroness Liliane Fould-Springer and asked her to marry him, which they did by proxy by 1942—Élie being allowed to take his marriage vows while imprisoned. Her mother thought her foolish to take on the Rothschild name with the Nazis in control of France. However, they were not troubled during the Nazi occupation. The Fould-Springers had extensive interests in Austria, and one branch of the family owned Château Beychevelle, a Bordeaux estate close to Château Lafite in Pauillac in the Médoc.

After the war, Élie, Alain and their wives shared the family mansion at avenue de Marigny, which had been used as the Luftwaffe headquarters during the war. Élie and his family moved to 11 rue Masseran in the 1950s, where he displayed his great collection of art, including works by Rembrandt, Gainsborough, Dubuffet and Picasso. This collection was described in the book "Great private collections", by Douglas Cooper; when Alvar Gonzales Palacios discovered a Dancer of Canova, he researched its history, and found out that, for a while, it had been in the Hotel Massaran, with the ridiculous attribution to Carpeaux.

He built a web of at least 20 secrecy-cloaked trusts in the South Pacific between 1996 and 2003, some of which continued operating after his death in 1997. As documents from the Offshore leaks revealed at least 20 trusts and 10 holding companies were set up for Rothschild in the Cook Islands, with typically opaque names including, fittingly, ″Anon Trust″. The companies have a common shareholder called ″Mandalor Limited″, an equally opaque company based in Saint Vincent and the Grenadines.

Élie was a friend of Prince Aly Khan and Gianni Agnelli. In 1954, when Liliane was out of town, Élie was introduced to divorcée Pamela Churchill (later Pamela Harriman). According to Élie, "She was sweet, charming and pretty. I wanted to go to bed with her and I did." Nevertheless, Liliane quickly saw off her rival. When the Duke of Windsor asked her: "Which Rothschild is the lover of Pamela Churchill?' she replied: "My husband, Sir".[citation needed] This remark undermined Pamela as much as any other retributive strikes and presently the affair receded. However, Élie de Rothschild met, in 1964, Eugenie Berkovics, who gave him a baby, Élie Jr. de Rothschild.[1] His nephew Éric de Rothschild, son of Alain, took over at Château Lafite-Rothschild in 1974.

Élie died of a heart attack when on vacation at his hunting lodge near the village of Scharnitz outside Innsbruck in Austria. His wife predeceased him in 2003. He is survived by a son, Nathaniel, and two daughters, Elisabeth and Nelly. He is also survived by a son, Elie Jr, (fathered with Eugenie Berkovics), and by a daughter (fathered with the Parisian antiquaire Ariane Dandois), Ondine, who bears the family name.[2] His son is married to Nili Limon, the daughter of Mordechai Limon, commander of the Israel Navy in the 1950s.[3]